Fluid-operated jack



. mmm

y H29, T. w. PEDERSEN FLUD OPERATED JACK [filed Dec. 5, 1924ZSheetS-Sheet l T. W1J PEDERSEN MAIM FLUID OPERATED V.mmm

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\ a um Patented July 9, 1929.

UNITED STATI-:s

PATENT OFFICE.

THOMAS W. PEDERSEN, OF NEW YORK. N. Y., ASSIGNOR TO OIL JACK, INO., OFNEW YORK, N. Y., A CORPORATION OF NEW YORK.

FLUID-OPERATED J ACK.

Application filed December 5, 1924. Serial No. 754,118.

. This invention relates te improvements in fluid-actuated jacks, andmore particularly to jacks that are self-contained and include meansi'or storing the. actuating (luid.

The principal object ot the invention is to provide ay jack ot? thistype which shall be generally more ellicient and durable than Others andshall be considerably less expensive to manufacture.

Another (,)bjcct is to provide. a fluid-operated jack with means forpositively preventing the forcing ot' the jack stem 'trom the cylinder.

A further object of fthe invention is to provide a {luid-operated jackwhich shall .be leak-proof and which may be carried in any positionwithout loss of l'luid.

'The invention further resides in certain novel and advantagi-iousdetails ot construction as hereinafter set forth and as illustrated inthe attached drawings, in which:

Figure 1 is an elevation of a jack made. in accordance with myinvention;

Fig. 2 is a plan view ot the jack;

Fig. 3 is a section ou the line 3 3, Fig. l, and

Fig. 4 is a fragmentary section on the line 4 4, Fig. 2.

With reference to the draw-ings, my jack comprises an integral bodymember l which may be of cast metal, said body having a niain chamber 2and a cylindrical sub-chamber 3 whose function will be describedhereinafter. rl`he chamber 2 has at the bottom a central cylindricalrecess or depression -1 for reception of the lower end 0i" a cylinder 5constituting the main cylinder of'the jack -in which the stem 6operates;

A valve fitting 7 also occupies a position in the recess 4, said fittinglying within the lower end of the cylinder 5 and having a reducedexternally threaded extension S extending down into a correspondinglythreaded recess 9 at the bottom ofthe recess 4.

r lvith the threaded extension 8' the fitting 7 may be screwed down upona cup-leather or other suitable packing 10 in the bottom of the recess4.

The fitting 7 is provided Wit-h a central passage l1 which opens at thetop into a recess l2, the passage 11 at: the point where it enters saidrecess being flared or otherwise formed to provide a seat for a ballvalve 13 which normally closes the said passage 1l. A rod lst extemlingacross the top of the ret-ess 12 prevents dislodgment of the ball 13from its chamber.

As shown in liig. il, the extension S of the litt-ing 7 does not reachthe bottom oli the recess 5), wherelrv a space 15 is let't; below thettting with which the passage ll. ronununicates, and a passage 1Gestablishes` communication between the said space 'l5 and the bottom ofthe chamber 3. lu the present instance, the passage 1G extends beyondthe chamber 3 to the outside ot' the body 1. The outer end of thepassage 1G may be closed. by a set screw 17 or other suitable preferablydetachable element.

The cvlinder 3 is recessed at the bottom tor the reception of a ballvalve 18, the latter linding a seat in the bottom of the recess 1t),from which a passage 20 extends to the. bottom ol" the chamber 2 outsideof the cylinder 5, as shown in Fig. 2l. The valve 18 normally closesthat end of the passage which opens into the recess 19.

'lhat portion of the body 1 enclosing the chamber 2 is provided at thetop with a threaded opening 21 through which the top of the stem or ram6 projects, and threaded into this opening 2l is a sleeve 22 having auannular recess 23 in its under side vlor reception ot the upper end ofthe cylinder 5 whereby when thc said sleeve 22 is screwed down intoplace against the top of the cylinder, the latter is clamped in properposition within the body l, seated at the, bottom in the said recess 4and held at the top w2ithin the annular recess 23 of the sleeve 2 Thecylinder 5 is provided at its top with a slot or other suitable opening2i which establishes communication between the interior of the cylinderand the space 25 ext'erioro't. the cylinder which, as hereinafter setforth, constitutes a reservoir for the operating fluid. l i' As shown inFig. 3, the ram or stem 6 is, over the greater portion of its length,slightly smaller than the inside of the cylinder 5, but has at. thebottom a section 2G ot increased diameter neat-ly titting'saidc'vlinder, this section guiding the ram in the cylinder. The steml 6 isprovided at the bot-A.

tom with a recess 27 threaded at its lower end for reception-of athreaded extension 28 on. a valve fitting 29. The stem is furtherprovided at the top of the section 26 with a cross channel 3() whichextends diametrically through the stem and through the upper end of therecess 27'. cross or contact bar 31, whose length is a'pproximately thesame as the diameter of the stem-section 26, and which is suitablyengaged with the upper end of a valve actuating stem 32 which extendsloosely through a central opening 33 in the fitting 29. The stem 32 isadapted to engage with its lower end a ball valve 34 seated in the upperend 'of the lower enlarged section 35 of the opening 33and'normallyretained on its seat by a spring 36 confined in the saidsection 35 by a stud 37 threadedl into the fitting. A sex-.ond spring 38is confined in the top of the recess 27 and functions normally to holdthe stem 32 and .bar 3l inA an elevated position', as shown in Fig. 3,in which position the ball 34 is seated and closing the opening 33. A

cup or other packing 39 is held between the tting 29 and the bottom ofthe st'em 6.

To prevent leakage of the actuating fiuid at the top of the chamber 2,suitable packing material 40 `may be inserted in the opening 21 aboveqthe sleeve 22 and surrounding the stem 6, and a gland 41 may then bethreaded down into said opening to compress and expand said packing. Theupper end 42 of the stem 6 is, in the present instance, threaded forreception of a loadengaging head 43.

The Achamber 3 is cylindrical in form and constitutes a pump cylinder,and is adapted for reception of a pump piston 44, to the bottom of whichis secured by a screw 46,

a suitable packing element 45. The piston extends upwardly through asuitable packing box-47 in the top Aof the chamber 3 and connects at thetop with a pump lever .48, see Figures 1, 2 and 3. The pump lever 48 ispivotally secured to a boss 49 on the body 1, by means in the presentinstance of a screw 50, and is connected with the piston 44 through alink 51 the 'ends of which are pivotally attached to the respectiveconnected arts. p As shown in Fig. 4, .the cylinder 5 is provided with aport 52 at a point immediately above the top of the valve fitting 7,said port opening into the reservoir 25. The port 52 is-adapled to beclosed by a needle valve 53, which extends through an opening 54 in thebody 1, the stem of said valve being threaded into a hollow stud 55which latter is in turn threaded into the opening 54. The stud 55 isadapted to receive packing'material which is confined by a gland 57threaded into the outer end of the stud, leakage around the valve stembeing thus prevented. The outer The channel, 30 receives a v projectingend of the said stem is provided with a suitable head 58 by which thevalve may be adjusted to close or uncover the port 52.

" As will be apparent, the actuating fluid is 'normally contained in thereservoir 25, and operation of the pump piston 44 by means of the lever4.8 will cause this fiuid first to be drawn into the bottom of the pumpchamber 3 through the. passage 20, and thereafter on the down stroke ofthe pump to be forced through the passage 16 and valve 13 into thebottom lof the cylinder 5. In this manner, the stem 6 may be elevateduntil the ends of the bar 31 strike the under side ofthe sleeve 22,whereupon the valve 34 will be opened by depression of the bar 3l, withthe result that a by-pass is provided for the fluid from below the stem6, through the opening 33 of the fitting 29, the channel 30, upwardlyaround the stem 6, and through the port 24 to the reservoir 25.Continued pumping merely circulates the fluid without ailecting thepressure on the stem 6.

.During elevation of thestem 6, the nee' lle valve 53 is closed, andwhen it is desired to return the' stem to its normal position, as

shown in Fig. 3, the needle valve may be adjusted, as previouslydescribed, to uncover the port 52, thereby permitting the fiuid to passfrom the. cylinder 5 back into the reservoir 25.

- It will be apparent that my improved ack, by reason of the integralconstruction ot the body, base and pump cylinder, made possible by theuse of the removable cylinder 5 and the means for holding the latter inposition,

is inexpensive to manufacture. The constructionis also such as to renderassembling the' jack easy, thereby further reducing expenseofmanufacture. It will further be noted that all openings by reason of theimproved construction m'ay be effectively packed against leakage, whichat the top of the cylinder' is further guarded against by provision of4the vent 24 through which leakage past the' bottom of the stem may bedrained backinto the reservoir. Provision 0f the valv'ed by-pass for thefluid, functioning after the stem 6 reaches the top of its -travel, alsois of marked advantage-as preventing undue pressure in the pump withpossible breakage of the parts and forcin of the stem Afrom thecylinder. i

It is, obvious that the jack as herein described may be considerablymodified in detail without departure from the essential features of theinvention as defined in the appended claim.

I claim:

A fluid opera-ted jack comprising a casing enclosing a reservoir; arecess in the base of said reservoir; a cylinder fitting into saidrecess and extending through said reservoir; a-stem in said cylinder ofa diameter smaller Mylan the internal diameter of the ylinder; a?.enlarged guide portion on said stemslidably tting said cylinder; abushing slidably fitting said stem and screwed into an open- 5 ing inthe reservoir casing for retaining the cylinder; a packing gland screwedinto the same opening in the reservoir casing; an

`aperture in the cylinder connecting the annular space between the stemand cylinder with 'the reservoir; a, pump; and means for concylinder. v

THOMAS W. lPEDERSEN.

